Since the Middle Ages, vagrants and thieves in Central Europe have spoken Rotwelsch, a secret language influenced by Yiddish and written in rudimentary signs. When Martin Puchner inherited a family archive, it led him on a journey into this extraordinary language but also into his family's connections to the Nazi Party, for whom Rotwelsch held a particular significance.

A riveting story of the mindset and milieu of Central Europe and of the way language can be used to evade oppression, The Language of Thieves is also a deeply moving reckoning with a family's buried past.